1. Field of the Invention
The present invention relates generally to sewn goods and to the method of making same. More particularly, the invention concerns a computer aided method that involves the use of fluorescent ink visible primarily under exciting radiation for communicating various instructions to computers and humans to aid in identifying cutting, transporting, assembling, ironing, packaging and shipping of various types of sewn articles.
2. Discussion of Prior Art
In the fabrication of sewn articles, such as clothing, footwear, and luggage various steps must be performed including the step of cutting the components that make up the sewn article to the correct size and shape and then sewing the components together to form the sewn article. These steps must be accomplished with great precision so that the various components that make up the garment are properly mated together to form the finished article.
Until relatively recently, the various steps involved in the fabrication of sewn goods, such as clothing, have been performed by hand. However, in the past several years a number of different types of machines, including high-speed sewing machines, have been developed to assist the worker in the fabrication of garments and to speed up the garment fabricating process. In addition to the development of high-speed sewing machines, high-speed fabric cutting devices and folders have also come into common use. However, even with the many advances that have been made, many of the steps in the garment fabrication operation are still being carried out by hand and the industry must still rely heavily upon the skill of the machine operator for identifying cutting, transporting, assembling, ironing, packaging and shipping of various types of sewn articles. The present state of the art is such that minor flaws are present on most finished sewn goods.
Since contemporary sewing machines can sew at speeds up to at least 9000 stitches per minute, proper hand orientation of components of the garment is very difficult and requires highly skilled operators. Because of the high-speed of modern sewing machines, even the most skilled operators have to stop frequently to check the accuracy of their work. Additionally, it is difficult for the operator to continuously feed the sheet materials to be joined through the machine while at the same time maintaining the correct alignment of the side edges thereof. This becomes even more difficult when the cloth components are made from a soft cloth material. In practice, therefore, the operator must, from time to time, stop the machine to manually adjust the alignment of the side edges of the sheet materials as they are fed toward the needle. This inevitably causes undesirable interruptions and delay in the sewing operation. Even though machines can operate at greater than 9000 stitches per minute, they are not able to utilize this great speed for any length of time due to such manual control of the machines. For foregoing reasons, even the use of the latest types of automatic sewing machines can be quite labor-intensive.
At the present time there is a great need in the garment fabricating industry to speed up production and to make smaller runs, while at the same time improving overall quality and repeatability. xe2x80x9cMass Customizationxe2x80x9dxe2x80x94 the manufacture of a single, custom made garment for just one person, for instance, is the direction in which the industry is moving. Thus greater flexibility in manufacturing machinery, and integrated solutions for assembly and finishing of garments is highly desirable. Changing stitches, correcting the feed, sewing along a curved path, sewing within tolerance zones, the ability to apply statistical process control, piece matching, automation, as for example, robotic positioning, pattern matching and error sensing are all extremely desirable. These features are particularly important as the market moves toward smaller lot sizes, and individual garment customization.
In this regard, due to the small lot size of individual runs, operators typically learn how to manufacture a particular size and type of garment. The lengths, pattern matching, fold tolerances and the like for the particular garment are largely maintained through operator interfacing. This mode of operation continues to rely heavily on well-trained operators and expensive operator training, monitoring, and quality control. However, even with careful training substantial amounts of material and labor is wasted due to mistakes in the learning process. Also, throughout the industry, there continues to be undesirably wide variations in the consistency of the final products that are produced.
In accordance with conventional prior art garment fabrication procedures, the CAD/CAM software links the design activity to the cutting machines. Cutting machines are driven by CAD/CAM files. This link, however, is virtually nonexistent between the design activity and the sewing machines. Once material is cut, operators must load and sew the material manually. For instance, an operator must insert the cloth into a sewing machine, then manually lower the feet onto the cloth to hold it in place, then press on a foot pedal to commence sewing and to control sewing speed. Assembly tolerance bands, as for example that of a stitch path, are maintained by the operator""s eye, hand, and foot coordination. Contemporary sewing speeds are such that small imperfections are hard to catch and it is easy to make a mistake. Accordingly, these processes place substantial demands on the operator requiring remarkable intensity and an alertness on the part of the operator if costly errors are to be avoided.
Because of the drawbacks of the prior art garment fabrication techniques as discussed in the preceding paragraphs, considerable effort has been directed toward creating a more automated manufacturing environment wherein operators do not have to be specially trained for each size, shape, and garment redesign. More specifically, an attempt has been made to develop a cloth marking technology that uses indicia that can be sensed by-machine control sensors. By way of example, U.S. Pat. No. 3,701,165 issued to Huddleson discloses such a technology. However, the Huddleson approach requires that the thread or ink contain iron oxide that is visible to the naked eye. Therefore, as a practical matter, this technology is useful only for marking areas on the garment that would ultimately be cut away or hidden in seams. This ferromagnetic technology also has the disadvantage that the iron oxide particles must be magnetically charged in order to be sensed by the control sensors thus requiring that some type of charging equipment be located at or near the sewing machine.
In using the Huddleson technology, garment parts which carry a magnetized mark or magnetized stitching are moved through an automated garment manufacturing process with the mark or stitching being detected by appropriate sensors. The sensed marks are then used as a reference point on the garment part to actuate various garment making steps, such as cutting, folding, stitching, and component interconnection.
In addition to the several types of cloth marking techniques that have been suggested, there exists a wealth of customized sewing machines that have been designed to perform a specific function. For example, in the production of a typical dress shirt, twenty or more different specialized machines may be used. In like manner, a number of customized sewing machines have been designed to produce a particular contour through the use of specially designed templates and special fixturing. For example, in making different pocket shapes, industry currently uses a pocket-making machine with hard fixturing for each unique shape. By way of further example, in accordance with long standing prior art garment fabrication methods, the size and shape of various garment components as well as pocket location, button hole location and the like on various types of garments was established using thin tissue paper templates. Such techniques are crude, imprecise are and labor intensive.
As will be better understood from the discussion that follows the methods and apparatus of the present invention will permit machines to be designed without focus on manual operation. Rather, in accordance with the novel methods of the present invention, a single machine can be used to perform many of the operations that currently require a number of separate machines. Additionally, the novel methods and apparatus of the present invention substantially eliminate the cumbersome and time consuming use of templates as well as the need for frequent manual measurement.
Another prior art practice that can be vastly improved using the methods and apparatus of the present invention involves component cutting, folding and transport. In accordance with prior art methods, paper pattern markers are typically laid on top of uncut layers of cloth so that when the cloth is cut, the stacks of pieces will be clearly identified. Then the stacks are manually moved to the assembly area. In accordance with one method of the present invention the use of pattern markers can be eliminated by printing the piece identifier directly on each piece using a radiation-excited invisible ink. Robotic cloth movement systems can then be employed to move and manipulate the components. In this regard, one major difficulty of prior art robotic movement systems was that they were unable to sense when the cloth was folded over upon itself. In accordance with the methods of the present invention, using radiation-excited invisible ink, a unique dot matrix pattern can be imprinted on each side of the cloth so that the sensing systems of the invention can readily determine which side of the cloth is face up. By sensing the distance between the individual dots of the pattern, the sensing system can also determine if the cloth is laying flat. Orientation markings can be provided to enable the robotic cloth movement system to acquire the orientation of the piece. Additionally, symbols can be printed on the pieces that would indicate where the piece is to be picked up by a robotic system, thus enabling automation of cloth movement. By way of further non-limiting example, in making button holes, the button hole locations can be identified by simply printing their locations on the cloth with appropriate invisible ink button hole symbols. Then by providing guidance markings, the machine can simply follow the orientation markings to the first button hole symbol, sew the first button hole, then follow the guidance markings to the next button hole and so on.
Many prior art attempts have been made to facilitate the making of garments with components that have patterns that match exactly. For example it is often desirable to manufacture a garment where the sleeve stripes are directly matched with the shoulder stripes or, additionally, a paisley shirt where the pocket paisleys match correctly with those on the front panel. One prior art method attempts to facilitate the cutting of the components in such a manner that the patterns on the cloth will match when the components are finally joined by projecting the outlines of the components of the garment onto the flat uncut cloth so that adjustments can be made prior to cutting. This involves much operator interfacing and can be time consuming and cumbersome. Employing the methods and apparatus of the present invention invisible fluorescent ink cutting instructions can be printed directly on the cloth prior to cutting, as for example, during the cloth printing step. The cloth cutting machines then sense these instructions and perform the cutting operation in such a manner that the components have patterns that match with great precision.
Another prior art method that aims to solve the pattern matching at the sewing machine is for example, U.S. Pat. No. 4,612,867. This patent describes sensing the variation in intensity of light reflected off two components that are to be matched, sensing alternating short and long patterns in order to then perform matching. The present invention offers an improved solution by requiring only that the invisible ink markings be sensed at the sewing machine in order to perform the aligning operation among components. For instance, a striped material can be printed with unique invisible fluorescent markings along the edge of each stripe. This later can be sensed to match adjoining parts in such a fashion that the stripes match precisely.
U.S. Pat. No. 4,404,919 and 4,658,741 provide methods for controlling the stitch length by counting the number of stitches. These methods have limited application since cloth is flexible and the length of a component, and hence the distance that must be sewn, varies according to how much the cloth has stretched. The use of invisible ink, on the other hand entirely solves this problem since the ink is joined to the cloth. If the ink instructions indicate that sewing is to continue from one point on the component to another, then stretching will not cause the sewing machine to sew short of the desired distance.
Many patents, such as U.S. Pat. No. 5,205,232, describe how to detect the edge of a cloth. With this present application, detecting the edge is no longer important since all operations are actuated based upon symbols sensed to the inside of the component perimeter thus eliminating the need for edge detection.
In summary, the present invention comprises a method and apparatus for computer aided sewn article fabrication wherein the article components are strategically imprinted with sensor as well as operator detectable indicia. The printed components are then moved through an automated sewn good manufacturing process wherein and the indicia is detected and used as reference points to actuate various manufacturing steps, such as cutting, folding, stitching, and relative positioning of garment components. In one form of the invention the detectable indicia comprises an ink that is either invisible or substantially invisible to the naked eye, but becomes visible under exciting radiation such as ultraviolet light. In this regard, it should be appreciated that the ink may be water soluble so that any residue will be gone after the first washing.
With the foregoing in mind, it is an object of the present invention to provide a novel method for computer aided sewn good fabrication in which human and sensor detectable, instructional indicia are imprinted at strategic locations on the material used to make the sewn good components.
Another object of the invention is to provide a method of the aforesaid character in which the detectable indicia imprinted on the material automatically and precisely controls the accomplishment of the various sewn good fabricating steps.
Another object of the invention is to provide a method of making garments as described in the preceding paragraphs in which the detectable ink used on the garment components is substantially invisible to the naked eye.
Another object of the invention is to provide an apparatus for accurately printing detectable indicia on the components that make up the sewn article.
Another object of the invention is to provide an apparatus for accurately detecting the indicia imprinted on the article components and for then performing various manufacturing processes in response to the detection of such marks or indicia.
Another object of the invention is to provide a method of making sewn goods in which full sewn good reproduction can be routinely achieved without noticeable variation in the completed sewn article that is produced by different operators.
Another object of the invention is to provide a method of making sewn goods as described in the preceding paragraph in which the quality of the sewn good produced does not depend on operator skill and experience.
The other objects, features, and advantages of the present invention will become apparent from the discussion, which follows.